Flexible air supply damper system for preventing overdrying-caused defect of secondary battery electrode plate

ABSTRACT

Provided is a flexible air supply damper system for preventing an overdrying-caused defect of a secondary battery electrode plate, the flexible air supply damper system including: a fluid supply unit supplying a fluid; a heating unit heating the fluid supplied through the fluid supply unit; a drying unit drying the electrode plate while receiving the fluid heated through the heating unit; a damper unit splitting the fluid passing through the heating unit to control an amount of the fluid to be introduced into the drying unit; and a discharge unit through which the fluid used in the drying unit and the fluid split out of the damper unit are discharged. By controlling the amount of the fluid to be introduced into the drying unit, the electrode plate is prevented from being overdried.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2020-0046734, filed on Apr. 17, 2020, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The following disclosure relates to a flexible air supply damper systemfor preventing an overdrying-caused defect of a secondary batteryelectrode plate capable of controlling a flow rate of air to be suppliedto a drying unit to prevent damage to the electrode plate caused whenthe electrode plate is overdried at the beginning of the drying process.

BACKGROUND

A device for drying a secondary battery electrode plate has apredetermined drying temperature and air volume for each section of adrying furnace. Since the electrode plate is dried in a state where thetemperature and the air volume are kept constant, the electrode plate isoverdried due to concentration-based drying at the beginning of thedrying process, resulting in a crack in the electrode plate, a break inthe electrode plate, and an increase in electrode resistance due tobinder migration. This has caused a problem that the quality of thedried electrode plate deteriorates.

Conventionally, in order to prevent such a problem, the followingmethods have been proposed: when the drying furnace is in operation, adoor of the drying furnace is opened to forcibly introduce externalfluid into the drying furnace, thereby resolving overheating; productionis performed after water is sprayed onto a substrate with a sprayer atthe beginning of operating the drying furnace to forcibly increase asolvent saturation amount in the drying furnace; and a temperature inthe drying furnace is lowered at the beginning of operating the dryingfurnace and adjusted to a target drying temperature simultaneously withproduction. However, the introduction of the external fluid forresolving overheating may cause a safety accident becauseflammable/toxic gas (NMP) generated during drying a positive electrodeplate is released to the outside, the spraying of the water for forciblyincreasing the solvent saturation amount in the drying furnace may causea problem that the positive electrode plate generating NMP during thedrying process may have a rapidly increasing NMP gas concentration, andthe lowering of the initial temperature and the adjusting of thetemperature to the target drying temperature simultaneously with theproduction may cause a problem that a time required for stabilizing thetemperature from the low temperature to the target temperature is notconstant, and thus, the electrode plate is not partially dried in thetemperature stabilizing process, resulting in a deterioration inproduction quality.

Therefore, there is a need for a new electrode plate drying systemcapable of solving such problems.

RELATED ART DOCUMENT Patent Document

Patent Document 1) Korean Patent Laid-Open Publication No.10-2018-0069388 (entitled “ELECTRODE DRYING DEVICE” and published onJun. 25, 2018)

SUMMARY

An embodiment of the present invention is directed to providing aflexible air supply damper system for preventing an overdrying-causeddefect of a secondary battery electrode plate capable of controlling anamount of hot air supplied to a drying furnace, when the system isrestarted after being stopped, to solve a problem of overheating of theelectrode plate at the beginning of the drying process.

Also, a specific aspect of such a system is proposed to maintain thesystem in a more efficient way.

Another embodiment of the present invention is directed to providing amethod for preventing overdrying using the flexible air supply dampersystem for preventing an overdrying-caused defect of a secondary batteryelectrode plate.

In one general aspect, a flexible air supply damper system forpreventing an overdrying-caused defect of a secondary battery electrodeplate includes: a fluid supply unit 100 supplying a fluid; a heatingunit 200 heating the fluid supplied through the fluid supply unit 100; adrying unit 300 drying an electrode plate while receiving the fluidheated through the heating unit 200; a damper unit 400 splitting thefluid passing through the heating unit 200 to control an amount of thefluid to be introduced into the drying unit 300; and a discharge unit500 through which the fluid used in the drying unit 300 and the fluidsplit out of the damper unit 400 are discharged.

The discharge unit 500 may include a discharge means 510 discharging thefluid, a first discharge passage 520 allowing the damper unit 400 andthe discharge means 510 to communicate with each other, and a seconddischarge passage 530 allowing the drying unit 300 and the dischargemeans 510 to communicate with each other.

The flexible air supply damper system may further include a circulationunit 600 reintroducing the fluid from the drying unit 300 via theheating unit 200.

The fluid supply unit 100 may include an introduction means 110introducing the fluid, and an introduction passage 120 guiding the fluidintroduced by the introduction means 110 to the heating unit 200.

The circulation unit 600 may include a circulation-supply means 610positioned between the introduction means 110 and the heating unit 200and supplying, to the heating unit 200, at least one of the fluidintroduced through the introduction means 110 and the fluid introducedthrough the drying unit 300, and a circulation passage 620 allowing thedrying unit 300 and the introduction passage 120 positioned between theintroduction means 110 and the circulation-supply means 610 tocommunicate with each other.

The flexible air supply damper system may further include a flow ratemeasurement unit 700 positioned on the circulation passage 620 tomeasure a flow rate of the fluid introduced into the introductionpassage 120 through the circulation passage 620 and provide informationon the measured flow rate to the discharge means 510.

The discharge means 510 may control an amount of the fluid to bedischarged based on the information on the flow rate received from theflow rate measurement unit 700 to keep an amount of the fluidcirculating through the circulation passage 620 constant.

In another general aspect, a drying method using the flexible air supplydamper system for preventing an overdrying-caused defect of a secondarybattery electrode plate includes: an introduction fluid flow ratedetermination step S100 of determining a flow rate of fluid to beintroduced through the fluid supply unit 100; a drying fluid temperaturedetermination step S200 of setting a temperature of the fluid to beintroduced into the drying unit 300; a drying fluid flow ratedetermination step S300 of controlling a flow rate of the fluid to beintroduced into the drying unit 300 from the damper unit 400; and adischarge fluid flow rate determination step S400 of determining a flowrate of the fluid to be discharged through the discharge unit 500,wherein in the drying fluid flow rate determination step S300, the flowrate of the drying fluid is determined as increasing in a stepwisemanner for a predetermined period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating a flexible air supply dampersystem for preventing an overdrying-caused defect of a secondary batteryelectrode plate according to a first exemplary embodiment of the presentinvention.

FIG. 2 is a flowchart illustrating a drying method using the flexibleair supply damper system for preventing an overdrying-caused defect of asecondary battery electrode plate according to the first exemplaryembodiment.

FIGS. 3A and 3B is each a table and a graph for explaining the electrodeplate drying method of the flexible air supply damper system forpreventing an overdrying-caused defect of a secondary battery electrodeplate according to the first exemplary embodiment.

FIGS. 4 and 5 are conceptual diagrams illustrating a flexible air supplydamper system for preventing an overdrying-caused defect of a secondarybattery electrode plate according to a second exemplary embodiment ofthe present invention.

FIGS. 6A and 6B is each a table and a graph for explaining the electrodeplate drying method of the flexible air supply damper system forpreventing an overdrying-caused defect of a secondary battery electrodeplate according to the second exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION OF MAIN ELEMENTS

-   -   100: Fluid supply unit    -   110: Introduction means    -   120: Introduction passage    -   200: Heating unit    -   300: Drying unit    -   400: Damper unit    -   500: Discharge unit    -   510: Discharge means    -   520: First discharge passage    -   530: Second discharge passage    -   600: Circulation unit    -   610: Circulation-supply means    -   620: Circulation passage    -   700: Flow rate measurement unit    -   S100: Introduction fluid flow rate determination step    -   S200: Drying fluid temperature determination step    -   S300: Drying fluid flow rate determination step    -   S400: Discharge fluid flow rate determination step

DETAILED DESCRIPTION OF EMBODIMENTS

The advantages and features of the present invention and methods foraccomplishment thereof will be clear from the exemplary embodiments thatwill be described in detail below with reference to the accompanyingdrawings. However, the present invention is not limited to the exemplaryembodiments to be described below and may be implemented in variouslydifferent forms. The exemplary embodiments are provided to complete thedisclosure of the present invention and for those skilled in the art tocompletely understand the scope of the present invention. The presentinvention is defined only by the claims. Like reference numerals denotelike components throughout the specification.

In describing the exemplary embodiments of the present invention, if itis determined that a detailed description of a known function orconfiguration may unnecessarily obscure the gist of the presentinvention, the detailed description thereof will be omitted. Further,the following terminologies are defined in consideration of thefunctions in the exemplary embodiments of the present invention and maybe construed in different ways by the intention or practice of users andoperators. Accordingly, they should be defined based on the contentsthroughout the specification.

Hereinafter, a flexible air supply damper system 1000 for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the present invention will be described with reference tothe accompanying drawings.

FIG. 1 is a conceptual diagram illustrating a flexible air supply dampersystem 1000 for preventing an overdrying-caused defect of a secondarybattery electrode plate according to a first exemplary embodiment of thepresent invention.

Referring to FIG. 1, the flexible air supply damper system 1000 forpreventing an overdrying-caused defect of a secondary battery electrodeplate according to the first exemplary embodiment of the presentinvention includes: a fluid supply unit 100 supplying a fluid; a heatingunit 200 heating the fluid supplied through the fluid supply unit 100; adrying unit 300 drying the electrode plate while receiving the fluidheated through the heating unit 200; a damper unit 400 splitting thefluid passing through the heating unit 200 to control an amount of thefluid to be introduced into the drying unit 300; and a discharge unit500 through which the fluid used in the drying unit 300 and the fluidsplit out of the damper unit 400 are discharged.

Specifically, when drying the secondary battery electrode plate, aheat-based drying scheme using a temperature and an air volume and aconcentration-based drying scheme using a solvent saturation amount areused together. However, there has been a problem that, when the systemis restarted after being shut down, since the solvent saturation amountin the drying unit does not reach a predetermined value, the electrodeplate is over-dried, resulting in a defect. The present invention isprovided to control an amount of the fluid to be introduced into thedrying unit 300 using the damper unit 400, thereby preventing theelectrode plate from being overdried when the same amount of fluid isintroduced into the drying unit in a state where the solvent saturationamount in the drying unit is low.

More specifically, a degree to which the electrode plate is dried iscontrolled based on the temperature and the amount of the fluidintroduced into the drying unit, in which the electrode plate is dried,and the solvent saturation amount in the drying unit. In this case, whenthe system is restarted, since the solvent saturation amount in thedrying unit 300 is low, if the fluid is introduced into the drying unit300 in an amount that is suitable when the solvent saturation amount isa predetermined value or higher, a concentration-based drying rate mayincrease and the electrode plate may be overdried. Thus, the amount ofthe fluid to be introduced into the drying unit 300 is controlled usingthe damper unit 400.

In addition, the discharge unit 500 includes a discharge means 510discharging the fluid, a first discharge passage 520 allowing the damperunit 400 and the discharge means 510 to communicate with each other, anda second discharge passage 530 allowing the drying unit 300 and thedischarge means 510 to communicate with each other. Specifically, thefluid split out of the damper unit 400 and the fluid discharged afterbeing used in the drying unit 300 are discharged by the discharge means510 after moving through the first discharge passage 520 and the seconddischarge passage 530, respectively.

FIG. 2 is a flowchart illustrating a drying method using the flexibleair supply damper system 1000 for preventing an overdrying-caused defectof a secondary battery electrode plate according to the first exemplaryembodiment, and FIG. 3 illustrates a table and a graph for explainingthe electrode plate drying method of FIG. 2.

Referring to FIG. 2, the drying method using the flexible air supplydamper system 1000 for preventing an overdrying-caused defect of asecondary battery electrode plate may include: an introduction fluidflow rate determination step S100 of determining a flow rate of thefluid to be introduced through the fluid supply unit 100; a drying fluidtemperature determination step S200 of setting a temperature of thefluid to be introduced into the drying unit 300; a drying fluid flowrate determination step S300 of controlling a flow rate of the fluid tobe introduced into the drying unit 300 from the damper unit 400; and adischarge fluid flow rate determination step S400 of determining a flowrate of the fluid to be discharged through the discharge unit 500. Theflow rate of the drying fluid, which is determined in the drying fluidflow rate determination step S300, may be determined as increasing in astepwise manner for a predetermined period of time.

Specifically, as described above, when a large amount of drying fluid isintroduced into the drying unit 300 in a state where the solventsaturation amount in the drying unit 300 is low, overdrying may occur.According to the present invention, as illustrated in FIGS. 3A and 3B,when the total amount of the fluid supplied to the heating unit 200 isdefined as 100% based on a trajectory-based amount using the damper unit400, 30% of the total amount of the fluid is supplied to the drying unit300 for about 60 seconds in step 1, 50% of the total amount of the fluidis supplied to the drying unit 300 for about 60 seconds in step 2, andthe amount of the fluid supplied to the drying unit 300 sequentiallyincreases in a stepwise manner in the next steps at time intervals untilthe final step N in which the solvent saturation amount in the dryingunit 300 increases to the predetermined value and all of the fluidheated while passing through the heating unit 200 is supplied to thedrying unit 300.

Therefore, since the flow rate of the fluid supplied to the drying unit300 increases in the stepwise manner at the time intervals, it ispossible to solve the overdrying problem that occurs when a large amountof drying fluid is supplied to the drying unit 300 at the beginning ofoperating the system. Also, since the amount of the fluid supplied tothe heating unit 200 is constant at all times, it is possible tominimize a range of fluctuation in temperature of the fluid supplied tothe drying unit 300.

FIGS. 4 and 5 are conceptual diagrams illustrating a flexible air supplydamper system 1000 for preventing an overdrying-caused defect of asecondary battery electrode plate according to a second exemplaryembodiment of the present invention.

Referring to FIG. 4, the flexible air supply damper system 1000 forpreventing an overdrying-caused defect of a secondary battery electrodeplate according to the second exemplary embodiment of the presentinvention further includes a circulation unit 600 reintroducing thefluid from the drying unit 300 via the heating unit 200. Specifically,the electrode plate positioned in the drying unit 300 is dried by thefluid heated in the heating unit 200. In this regard, there has been aproblem in that, in order to keep the flow rate and temperature of thefluid introduced into the drying unit 300 constant, a lot of energy isconsumed because fresh air introduced through the fluid supply unit 100needs to be heated all over again. In addition, there has been anotherproblem in that, when new air is supplied to the heating unit 200through the fluid supply unit 100, a range of fluctuation in solventsaturation amount in the heating unit 200 increases. According to thepresent invention, the circulation unit 600 is used to mix the air fromthe drying unit 300 with the air newly introduced through the fluidsupply unit 100.

When the air from the drying unit 300 is mixed in the fluid supply unit100, a flow rate of the circulating fluid is added to that of the fluidintroduced through the fluid supply unit 100, thereby reducing energyconsumption in the fluid supplying process.

Further, referring to FIG. 4, the fluid supply unit 100 includes anintroduction means 110 introducing the fluid, and an introductionpassage 120 guiding the fluid introduced by the introduction means 110to the heating unit 200, and the circulation unit 600 includes acirculation-supply means 610 positioned between the introduction means110 and the heating unit 200 and supplying, to the heating unit 200, atleast one of the fluid introduced through the introduction means 110 andthe fluid introduced through the drying unit 300, and a circulationpassage 620 allowing the drying unit 300 and the introduction passage120 positioned between the introduction means 110 and thecirculation-supply means 610 to communicate with each other.

Specifically, allowing the drying unit 300 and the introduction passage120 to communicate with each other through the circulation passage 620,the circulation unit 600 forms a path through which the fluid from thedrying unit 300 may circulate, and supplies, to the drying unit 300, thefluid in which the fluid from the drying unit sucked by thecirculation-supply means 610 is mixed with the fluid introduced throughthe introduction means 110.

In addition, referring to FIG. 4, the flexible air supply damper systemfor preventing an overdrying-caused defect of a secondary batteryelectrode plate according to the present invention further includes aflow rate measurement unit 700 positioned on the circulation passage 620to measure a flow rate of the fluid introduced into the introductionpassage 120 through the circulation passage 620 and provide informationon the measured flow rate to the discharge means 510. The dischargemeans 510 may control an amount of fluid to be discharged based on theinformation on the flow rate received from the flow rate measurementunit 700 to keep an amount of fluid circulating through the circulationpassage 620 constant.

Specifically, in order to stably dry the electrode plate, it isimportant to control a flow rate of fluid to be supplied to be keptconstant. Thus, according to the present invention, the flow ratemeasurement unit 700 is positioned to detect an amount of thecirculating fluid on the circulation passage 620, and information on theflow rate measured by the flow rate measurement unit 700 is provided tothe discharge means 510 capable of controlling an amount of thecirculating fluid, such that the discharge means 510 may control anamount of fluid to be discharged based on the received information tocontrol an amount of fluid to be supplied to the circulation-supplymeans 610 through the circulation passage 620.

In this case, the circulation-supply means 610 may be any type of devicecapable of controlling an amount of fluid to be discharged, and may be afan whose blades rotate to move the fluid as an example. In addition,the introduction means 110 and the discharge means 510 may be the samedevice. In the present invention, the fluid refers to any type of fluidthat can be used for drying, and may be air as an example.

FIG. 6 is a table and a graph for explaining the electrode plate dryingmethod of the flexible air supply damper system 1000 for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the second exemplary embodiment of the present invention.

Referring to FIGS. 4 and 5, when the damper unit 400 splits theintroduced fluid to control a flow rate of the fluid to be introducedinto the drying unit 300, only some of the fluid introduced into theheating unit 200 is introduced into the drying unit 300 if the damperunit 400 is partially opened as illustrated in FIG. 4, or all of thefluid introduced into the heating unit 200 is introduced into the dryingunit 300 if the damper unit 400 is fully opened as illustrated in FIG.5. Accordingly, the present invention is capable of solving theelectrode plate overdrying problem at the beginning of the dryingprocess by increasing a degree to which the damper unit 400 is opened ina stepwise manner, as illustrated in FIGS. 6A and 6B, in a state wherethe amount of the circulating fluid is kept constant.

In the drawings, it is illustrated that a trajectory-based amountmaintaining time is set to 60 seconds, but this is an example. When thefluid from the drying unit 300 circulates through the circulation unit600, the solvent saturation amount in the drying unit 300 is stabilizedfaster, and the temperature of the fluid can be more stably controlledresulting from a reduced difference between a temperature of the fluidbefore being heated and a target temperature which the fluid needs toreach after passing through the heating unit 200. This also makes itpossible to reduce the trajectory-based amount maintaining time ascompared with that when the circulation unit 600 is not provided.

The flexible air supply damper system for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the present invention is advantageous in that an amount ofhot air introduced into the drying unit can be controlled using thedamper unit, thereby solving the overdrying problem that occurs when thedrying device is restarted after being stopped.

Further, the flexible air supply damper system for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the present invention is also advantageous in that thedamper unit controlling an amount of fluid to be introduced into thedrying unit is positioned between the heating unit adjusting atemperature of the fluid and the drying unit drying the electrode plateusing the heated fluid, thereby keeping the amount of fluid to besupplied to the heating unit constant.

Specifically, if the amount of the fluid introduced into the heatingunit fluctuates, the temperature of the fluid having passed through theheating unit cannot be kept constant. Thus, the damper unit controllinga flow rate of the fluid is positioned at a rear end of the heating unitto keep the temperature of the fluid to be introduced into the dryingunit constant at all times.

Further, the flexible air supply damper system for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the present invention is also advantageous in that thefluid used for drying can be circulated for reuse, thereby quicklyincreasing an initial solvent saturation amount in the drying unit to apredetermined value and minimizing energy consumption in heating thefluid.

In addition, the flexible air supply damper system for preventing anoverdrying-caused defect of a secondary battery electrode plateaccording to the present invention is also advantageous in that thedischarge means and the flow rate measurement unit communicate with eachother to control an amount of circulating fluid to be constant, therebykeeping a flow rate of fluid to be introduced into the drying unitconstant.

The present invention is not limited to the above-described exemplaryembodiments, and may be applied in various ways. Various modificationscan be made by any person having ordinary knowledge in the field towhich the present invention pertains without departing from the gist ofthe present invention claimed in the appended claims.

What is claimed is:
 1. A flexible air supply damper system comprising: afluid supply unit supplying a fluid; a heating unit heating the fluidsupplied through the fluid supply unit; a drying unit drying anelectrode plate while receiving the fluid heated through the heatingunit; a damper unit splitting the fluid passing through the heating unitto control an amount of the fluid to be introduced into the drying unit;and a discharge unit through which the fluid used in the drying unit andthe fluid split out of the damper unit are discharged.
 2. The flexibleair supply damper system of claim 1, wherein the discharge unit includesa discharge means discharging the fluid, a first discharge passageallowing the damper unit and the discharge means to communicate witheach other, and a second discharge passage allowing the drying unit andthe discharge means to communicate with each other.
 3. The flexible airsupply damper system of claim 1, further comprising a circulation unitreintroducing the fluid from the drying unit via the heating unit. 4.The flexible air supply damper system of claim 3, wherein the fluidsupply unit includes an introduction means introducing the fluid, and anintroduction passage guiding the fluid introduced by the introductionmeans to the heating unit.
 5. The flexible air supply damper system ofclaim 4, wherein the circulation unit includes a circulation-supplymeans positioned between the introduction means and the heating unit andsupplying, to the heating unit, at least one of the fluid introducedthrough the introduction means and the fluid introduced through thedrying unit, and a circulation passage allowing the drying unit and theintroduction passage positioned between the introduction means and thecirculation-supply means to communicate with each other.
 6. The flexibleair supply damper system of claim 5, further comprising a flow ratemeasurement unit positioned on the circulation passage to measure a flowrate of the fluid introduced into the introduction passage through thecirculation passage and provide information on the measured flow rate tothe discharge means.
 7. The flexible air supply damper system of claim6, wherein the discharge means controls an amount of the fluid to bedischarged based on the information on the flow rate received from theflow rate measurement unit to keep an amount of the fluid circulatingthrough the circulation passage constant.
 8. A drying method using theflexible air supply damper system of claim 1, the drying methodcomprising: an introduction fluid flow rate determination step ofdetermining a flow rate of fluid to be introduced through the fluidsupply unit; a drying fluid temperature determination step of setting atemperature of the fluid to be introduced into the drying unit; a dryingfluid flow rate determination step of controlling a flow rate of thefluid to be introduced into the drying unit from the damper unit; and adischarge fluid flow rate determination step of determining a flow rateof the fluid to be discharged through the discharge unit, wherein in thedrying fluid flow rate determination step, the flow rate of the dryingfluid is determined as increasing in a stepwise manner for apredetermined period of time.